System and method for palletizing

ABSTRACT

A palletizing elevator is provided that lowers gradually a pallet thereon from an upper level as it is filled with products, and by providing an empty pallet infeed system that moves empty pallets towards the palletizing elevator simultaneously to the palletizing of products thereon. The empty pallet infeed system includes an empty pallet elevator for raising empty pallets to the upper level and a conveying system between the empty pallet elevator and the palletizing elevator for moving the empty pallets of from the empty pallet elevator at the upper level to the palletizing elevator while a pallet is moved by the palletizing elevator during its filling.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/533,392, filed Aug. 6, 2019, (now U.S. Pat. No. 10,934,107), which isa continuation of U.S. patent application Ser. No. 15/235,254, filedAug. 12, 2016, (now U.S Pat. No. 10,370,199), which is a non-provisionalof and claims the benefit of U.S. Provisional Application No.62/204,157, filed on Aug. 12, 2015, the contents of which areincorporated by reference herein in their entireties.

BACKGROUND 1. Field

The present disclosure relates to palletizing, and more specifically toa system and method for palletizing.

2. Brief Description of Related Developments

Many robotic palletizing cells are known in the art. Typically, such apalletizing cell includes one or more robot arms equipped with a productpicking tool, a system that brings an empty pallet near the robot arms,and one or more conveyors that brings products to the robots to bepicked thereby and positioned on the pallet.

A drawback of conventional palletizing cells is that there is waitingtime inherent to the bringing of an empty pallet near the robot arms andof the exiting of a full pallet before a further pallet is filled withproducts.

Also, the new requirements of manufacturers and distribution centers askfor better productivity of the robotic arm, where waiting time should beminimized.

SUMMARY

The problem of waiting time in a palletizing system is solved byproviding a palletizing elevator that lowers gradually as a palletthereon is filled with products and by providing an empty pallet infeedsystem that moves empty pallets towards the palletizing elevatorsimultaneously to the palletizing of products thereon.

According to an illustrative embodiment, there is provided a palletizingsystem comprising:

A palletizing elevator for receiving a first pallet at an upper leveland for moving the first pallet from the upper level to a lower level asproducts are being moved onto the first pallet;

At least one product picking apparatus for picking products adjacentthereof and for moving the products onto the first pallet on thepalletizing elevator;

An empty pallet elevator for moving a second pallet to the upper level;and

An empty pallet conveying mechanism between the empty pallet elevatorand the palletizing elevator for moving, at the upper level, the secondpallet from the empty pallet elevator to the palletizing elevator.

According to a further illustrative embodiment, there is provided asystem for the simultaneous infeed of empty pallets and outfeed of afull pallet, the system comprising:

A palletizing elevator for receiving one of the empty pallets at anupper lever and for lowering same from the upper level to a lower levelas products are moved onto said one of the empty pallets;

An empty pallet elevator for raising another one of the empty pallets tothe upper level; and

A conveying system at the upper level between the empty pallet elevatorand the palletizing elevator for moving said another one of the emptypallets from the empty pallet elevator to the palletizing elevator whilesaid one of the empty pallets is moved by the palletizing elevatorduring a filling thereof.

According to another embodiment, there is provided a palletizing systemcomprising:

A frame;

A platform supported by the frame that generally defines an upper level;

A palletizing elevator for receiving a first pallet at an upper leveland for moving the first pallet from the upper level to a lower level asproducts are being moved onto the first pallet; the palletizing elevatorcomprising a pallet-receiving element that is mounted to the frame forreciprocating movement towards and away the platform;

At least one product picking apparatus for picking products adjacentthereof and for moving the products onto the first pallet on thepalletizing elevator;

An empty pallet elevator for moving a second pallet to the upper level;the empty pallet elevator including a pallet-receiving platform that isslidably mounted to the frame; and

A telescopic fork between the empty pallet elevator and the palletizingelevator for moving, at the upper level, the second pallet from theempty pallet elevator, to the palletizing elevator;

At least one product infeed conveyor that is positioned at the upperlevel within reach of the at least one product picking apparatus formoving products adjacent to the at least one product picking apparatus;and

The platform including an aperture over the palletizing elevator,adjacent the product picking apparatus, that allows passage for thefirst pallet and for the products that are moved thereon.

According to still another illustrative embodiment, there is provided apalletizing method comprising:

Receiving products to be palletized on a raised platform;

Repeatedly and simultaneously:

Raising a first empty pallet to the raised platform;

Moving a second empty pallet towards a palletizing area defined by anaperture in the raised platform; and

Moving the products on a third pallet at the palletizing area until thethird pallet is filled while the third pallet is lowered from the raisedplatform so that an upper level of the products on the third palletremains generally levelled with the palletizing area;

Exiting the third pallet from under the palletizing area.

The palletizing system and method according to the first illustrativeembodiment allows reducing a waiting time to basically zero.

Other objects, advantages and features of the palletizing system andmethod will become more apparent upon reading the followingnonrestrictive description of preferred embodiments thereof, given byway of example only with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings:

FIG. 1 is a top perspective of palletizing system according to a firstillustrative embodiment; the system being shown with the empty palletelevator at its upper position and the palletizing elevator at its lowerposition;

FIG. 2 is a top perspective of the palletizing system from FIG. 1; thesystem being shown with the empty pallet elevator at its lower positionand the palletizing elevator at its upper position;

FIG. 3 is a side perspective of the palletizing system from FIG. 1; thesystem being shown with its telescopic fork extended towards thepalletizing elevator;

FIG. 4 is a close-up partly isolated first side perspective of the emptypallet elevator and telescopic fork of the system from FIG. 1; theelevator being shown in its upper position and the fork partiallyextended in its direction;

FIGS. 5 to 7 are close-up partly isolated second side perspective of theempty pallet elevator and telescopic fork of the system from FIG. 1,illustrating the operation thereof; and

FIG. 8 is a flowchart of a palletizing method according to anillustrated embodiment.

DETAILED DESCRIPTION

In the following description, similar features in the drawings have beengiven similar reference numerals, and in order not to weigh down thefigures, some elements are not referred to in some figures if they werealready identified in a precedent figure.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one”, butit is also consistent with the meaning of “one or more”, “at least one”,and “one or more than one”. Similarly, the word “another” may mean atleast a second or more.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “include” and “includes”) or “containing”(and any form of containing, such as “contain” and “contains”), areinclusive or open-ended and do not exclude additional, unrecitedelements.

A palletizing system 10 according to a first illustrative embodimentwill now be described with reference to FIGS. 1 to 3. The expression‘palletizing cell’ will also be used to refer to the palletizing system10.

The palletizing system 10 comprises a palletizing elevator 12 forgradually lowering a pallet from a second level 11 to a first level 13as products are being moved thereon, two product picking apparatuses 14,each for picking products (not shown) from an adjacent infeed conveyor16 and for moving the products onto the pallet on the palletizingelevator 12, an empty pallet elevator 18 for supplying empty pallets(not shown) to the second level 11; and an empty pallet conveyingmechanism between the empty pallet elevator 18 and the palletizingelevator 12 for moving empty pallets 21 from the second level of theempty pallet elevator 18 to the palletizing elevator 12.

As an input, products (not shown), that can be of various sizes, arrivevia the infeed conveyors 16 and are picked by one of the product pickingapparatuses 14 and placed at a palletizing area 23, which corresponds tothe portion of the palletizing elevator 12 on the upper level 11.Simultaneously to this operation, the empty pallet elevator 18 brings anempty pallet 21 to the empty pallet conveying mechanism 20. Themechanism 20 transfers the empty pallet 21 from the empty palletelevator 18 to the palletizing area 23. The elevator 12 takes over thepallet 21 and lowers the pallet 21 as the products are being palletized.As an output, a full pallet (not shown) made from a variety of productsis ready to be pick up by a forklift or else at the lower portion of thepalletizing elevator 12.

The expression “product” should be construed herein as including anytype of case, carton, tray, shrink wrapped bundle, etc.

Generally, the product is of a rectangular shape. The product dimensionsmay vary greatly between each different types of product. Typicaldimensions (W×L×H) are between 4″×6″×2″ (10,16 cm×15,24 cm×5,08 cm) and20″×25″×24″ (50,8 cm×63,5 cm×60,96 cm).

Also, the pallet is not limited to the illustrated embodiment and thesystem 10 can be adapted to any form of pallet.

Each of the above-cited components of the system 10 and other featuresand characteristics thereof will now be described in more detail.

As hinted hereinabove, the palletizing cell 10 includes a lower level13, and an upper level 11, that is defined by a raised platform 22. Thisplatform 22 and the equipment thereon are supported on a frame 24. Theheight of the platform 22 is mainly determined by the clearance requiredby the maximum height of a pallet filled by the system 10 on thepalletizing elevator 12.

The frame 24 may be formed by integrated frame elements or by adjacentindependent sub-platform, each supporting one or more components of thepalletizing system 10.

The product picking apparatuses 14 are in the form for example ofstandard industrial articulated robot arms 26 suitable for theapplication, each operatively positioned adjacent to the infeed conveyor16 and being equipped with an end of arm tool 28 to pick products on theinfeed conveyor 16.

In the description and in the claim, the expressions ‘robot’ and ‘robotarm’ will be used interchangeably to mean a programmable systemincluding articulated and/or movable members that can receive, controland move a tool.

A conventional robot arm can be used, such as ABB's or IRB 460 or 4600,FANUC's M410 or R2000, or any similar robot arm offered by othermanufacturers such as Kuka or Motoman.

According to the illustrated embodiment, the end of arm tool 28 issimilar to the one described in United States Patent Publ. No.US-20150314455-A1 published on Nov. 5, 2015 and titled “Method and Toolfor Palletizing Mixed Load Products.”

The system 10 is however not limited to including such a tool, which canbe adapted or changed depending for example on the products to bepalletized.

Since the operation of a robot and of a robot controller is believed tobe well known in the art, it will not be described herein in more detailfor concision purposes.

The infeed conveyors 16 are also not limited to any particularembodiment, and any conveying mechanism can be used to move productsreceived on the upper level 11 within reach of the product pickingapparatuses 14.

Turning briefly to FIG. 4, where the robot arms 14 and the palletizingelevator 12 were removed to alleviate the view, the empty palletelevator 18 will now be described in more detail.

The elevator 18 comprises a pallet-receiving platform 30 that is mountedto a wall 32 for slidable movement therealong. The wall 32 extends fromthe first to the second levels 13 and 11 and is secured to the frame 24on a peripheral side thereof.

The platform 30 includes a bottom 34 fixedly mounted to two side walls36 therebetween. The side walls 36 are slidably mounted to the wall 32via sliding elements, such as without limitations rollers (not shown) intracks 38.

The up and down movements of the platform 30 along the wall 32 isactuated by a drive 40, which is operatively coupled to the platform 30via a belt assembly 42 secured to the wall 32 and to the platform 30therebetween.

The platform 30 is configured and sized for receiving a pallet 21thereon and for slidingly receiving part of the empty pallet conveyingmechanism 20 as shown in FIG. 4. The platform is not limited to any sizeand shape and is adapted for a predetermined size and configuration ofpallet. According to another embodiment (not shown), the platform 30 isdefined by fork elements.

The empty pallet elevator 18 is not limited to the illustratedembodiment and can be provided with any other mechanisms to selectivelylower and raise the empty pallet receiving platform 30.

Returning to FIGS. 1 to 3, the palletizing elevator 12 is distanced fromthe empty pallet elevator 18 by the empty-pallet conveying mechanism 20and extends between the first and second levels 13 and 11 similarly tothe empty pallet elevator 18.

The platform 22 includes a rectangular aperture 44 that allows passage1) to an empty pallet 21 from the empty pallet conveying mechanism 20onto the elevator 12 and then 2) for the end of arm tool 28 and productsthereon. The aperture 44 is located in the palletizing area 23 whereinthe product-picking apparatuses 14, which are on opposite side thereof,bring products picked on the respective infeed conveyors 16.

As already mentioned, the palletizing elevator 12 gradually lowers asproducts are put onto the pallet 21 so that the top level of the highestproduct on the pallet 21 remains generally levelled with the platform22.

With references to FIGS. 1 to 3, the palletizing elevator 12 comprises agenerally rectangular pallet-receiving element 46 supported by a frame48. The frame 48 is slidably mounted to the frame 24 via an actuatingmechanism 45 for reciprocating movement of the frame 48 andpallet-receiving element 46 generally between the upper and lower level11 and 13.

The frame 48 includes two (2) first parallel beams 47 (only one shown)secured to two (2) second parallel beams 49 transversally thereto. Theframe 48 receives three (3) transversal chain assemblies 50 thereon.

Each chain assemblies 50 comprises an endless chain 52 that isoperatively mounted to the frame structure 48 via a sprocket assembly54, for rotation along an axis defined by the conveying direction of apallet on the empty pallet conveying mechanism 20. The chain assemblies50 together define a movable pallet-receiving element 46.

Since the configuration and operation of a chain assembly is believed tobe well-known in the art, the assemblies will not be described herein inmore detail for concision purposes.

The number and configuration of the chain assemblies 50 are also notlimited to the illustrated embodiment. Also, the pallet-receivingelement 46 is not limited to being movable and other mechanism can beprovided to move a pallet 21 in or out of the palletizing elevator 12.

The actuating mechanism 45 comprises four (4) chain assemblies 56 thatare secured to both frames 24 and 48 therebetween and that are operatedby a drive 58.

More specifically, each chain assembly 56 includes a chain 60 that isrotatably mounted to the frame 24 in an endless manner via two sprocketwheels 62 or 63 (only the lower ones shown). The chain 60 generallyextends between the platform 22 and the lower level 13 along a directiongenerally perpendicular to the platform 22.

The chain assemblies 56 are interconnected for rotation in unison, firstby two shafts 64 coaxially mounted to each two facing pairs of sprockets62 and 63, and second by a gear assembly 66 operatively linking twoadjacent sprockets 63, one from each of the afore-mentioned pairs. Thedrive 58 includes a motor 68 that is coupled to the gear assembly 66.The motor 68 has a built-in brake system. Each of the adjacent sprockets63 is coupled with a disk brake 70 to ensure a safe descent of thepalletizing elevator.

The frame 48 is fixedly mounted to each of the four chains 60 formovement in unison therewith via four (4) brackets (only two shown) thatare secured to the frame 48.

In operation of the palletizing elevator 12, the controlled actuation ofthe drive 58 causes the four lower sprocket wheels 62 and 63 to rotatein a same direction, causing the chains 60 to rotate in unison in anendless manner, causing the pallet-receiving element 46 tocorrespondingly lower or raise between the upper and lower levels 11 and13 via the frame 48. The drive 58 operates in such a manner that thepallet-receiving element 46 lowers incrementally by step distancescorresponding to the heights of each level of products added to thepallet 21. However, the raising movement of the pallet-receiving element46 is continuous so as to bring back said element 46 to the upper level11 ready to be filled with new products after a full pallet 21 has beenremoved thereon at the lower level 13.

The palletizing elevator 12 includes a further actuator (not shown) thatis coupled to the chain assemblies 50 to cause the selective translationof the pallet-receiving element 46 to move a pallet filled with productsout of the palletizing elevator 12 when the pallet-receiving element 46is at the lower level 13.

The palletizing elevator 12 is not limited to the illustrated embodimentand can be provided with any other mechanisms to lower and raise thepalletizing element 46.

The palletizing element 46 is also not limited to the illustratedembodiment. For example, the chain assemblies 50 can be replaced byanother pallet conveying mechanism or be omitted.

Turning now to FIGS. 5 to 11, the empty pallet conveying mechanism 20will now be described. According to the first embodiment, the mechanism20 is in the form of a telescopic fork.

The telescopic fork 20 comprises a drive 74, a first stage 76 that isfixedly mounted to the frame 24, a second stage 78 that is slidablymounted to the first stage 76 for relative translation between twoopposite longitudinal directions, and a third stage 80 that is slidablymounted to the second stage 78 for relative translation along same twoopposite directions (see arrows 82 and 84 in FIG. 8).

According to the illustrated embodiment, the mechanism of the telescopicfork 20 includes a three stage system using carriages and belts in orderto extend the telescopic forks from one end to the other.

FIGS. 5 to 7 shows the extent of movements or reach of the telescopicfork 20. As can be seen from these figures, the position and reach ofthe telescopic fork 20 is such that the third stage 80 overlays thepallet-receiving platform 30 of the empty pallet elevator 18 when thefork 20 is fully extended in that first direction (see FIG. 5) andoverlays the palletizing area 44 when it is fully extended in thatsecond direction (see FIG. 7). FIG. 6 shows the telescopic fork 20 inits un-extended neutral position. FIG. 7 further illustrates theminimizing of wait time, with the empty-pallet elevator 18 bringing anempty pallet to the telescopic fork 20 while the telescopic fork 20brings another empty pallet 21 to the palletizing area 44.

According to another embodiment (not shown), some of the belts arereplaced by a rack and pinion system to move the telescopic forks fromone end to the other.

The operation of the palletizing system 10 will now be described withreference to FIGS. 1 to 7 and to an illustrative embodiment of apalletizing method 200 as shown in FIG. 8.

An empty pallet conveyor (not shown) brings empty pallets 21 one by oneto the empty pallet elevator 18 (step 202). Once an empty pallet 21 ison the platform 30, the elevator 18 lifts the empty pallet 21 to theupper level 11 of the system 10 (step 204).

The palletizing system 10 includes, in some embodiment, a centeringdevice (not shown) that centers the empty pallet 21 once it reaches theupper level 11 (step 206).

The telescopic fork mechanism 20 is extended underneath the empty pallet21 brought by the elevator 18 to remove it from the elevator's platform30 (step 210).

Moving to the opposite direction, the telescopic fork 20 brings theempty pallet 21 to the palletizing area 44 (step 212).

When the empty pallet 21 clears the empty pallet elevator's platform 30,as it is transferred on the telescopic fork 20; the platform 30 islowered to pick the next empty pallet 21 supplied by the empty palletconveyor (step 208).

In the meantime, as the empty pallet 21 reaches the palletizing area 44,the robots 14 start palletizing products (not shown) who are supplied bythe product infeed conveyors 16, using its end of arm tool 28 (step216).

When the pallet is supported by the palletizing elevator (step 217), thetelescopic forks 20 move to towards the empty pallet elevator 18 to takethe next empty pallet 21 (step 214) that was in the meantime raised bythe elevator 18 (step 204).

As more products are added on the pallet by the robots 14, thepalletizing elevator 12 is lowered so that the top level of the productson the pallet being filled remains in the palletizing area 44 (step218).

The palletizing elevator lowers the pallet in steps as more products arebeing palletized by the robots 14.

As the palletizing elevator 12 lowers the pallet, the palletizedproducts are stretched wrapped (step 220).

When the palletizing sequence is completed, the palletizing elevator 12lowers the full pallet (step 222) to be transferred for example to afull pallet exit conveyor (not shown) (step 224).

As the pallet exits the palletizing cell, the palletizing elevator 12 israised to hold a new pallet 21 in the palletizing area 44.

This above sequence is repeated as the products are being palletized.

The components of the system 10, such as the robots 14, productconveying systems 16, palletizing and empty pallet elevators 12 and 18,and empty pallet conveying mechanism 20 are coupled and controlled by asingle or a plurality of controllers or electronic devices (both notshown), including for example one or more computers, that are configuredwith components and/or programmed with instructions that produce one ormore functionalities.

It is to be noted that many other modifications could be made to thepalletizing system and method described hereinabove and illustrated inthe appended drawings. For example:

while the illustrated embodiment is shown and described having two robotarms, a single one can also be used;

each or both of the robot arms can be replaced by a gantry typeequipment or any other similar means;

the telescopic fork mechanism movement can be actuated by a standardrack and pinion system;

the telescopic fork mechanism could be replaced by another empty palletconveying system such as a pusher system, a conventional conveyor systemor a shuttle system;

the empty pallet infeed conveyor can be replaced by other means tosupply empty pallet to the empty pallet elevator;

the full pallet outfeed conveyor can be replaced by other means toremove full pallets.

It is to be understood that embodiments of the palletizing system andmethod are not limited in their application to the details ofconstruction and parts illustrated in the accompanying drawings anddescribed hereinabove. Other embodiments can be foreseen and practicedin various ways. It is also to be understood that the phraseology orterminology used herein is for the purpose of description and notlimitation.

What is claimed is:
 1. A palletizing system comprising: a palletizingelevator for receiving a first pallet at an upper level and for movingthe first pallet from the upper level to a lower level as products arebeing moved onto the first pallet; at least one product pickingapparatus for picking products adjacent thereof and for moving theproducts onto the first pallet on the palletizing elevator; an emptypallet elevator for moving a second pallet to the upper level; and anempty pallet conveying mechanism with an expanding/contracting stagebetween the empty pallet elevator and the palletizing elevator formoving, at the upper level, the second pallet from the empty palletelevator to the palletizing elevator, the expanding/contracting stageexpanding and contracting between a retracted position and first andsecond extended positions respectively on opposite sides of theretracted position and respectively over the empty pallet elevator andthe palletizing elevator, so that a common stage of theexpanding/contracting stage, having an empty pallet support surface thatis common to each of the first and second pallet, is in the firstextended position over the empty pallet elevator and in the secondextended position over the palletizing elevator on the opposite side ofthe retracted position from the empty pallet elevator, wherein each ofthe first, second extended and retracted positions are disposed at theupper level.
 2. The system of claim 1, further comprising: a frame; aplatform, supported by the frame, that generally defines the upperlevel; and the palletizing elevator comprising a pallet-receivingelement that is mounted to the frame for reciprocating movement towardsand away the platform.
 3. The system of claim 2, wherein the platformincludes an aperture over the palletizing elevator, adjacent the productpicking apparatus, that allows passage for the products that are movedthereon.
 4. The system of claim 2, wherein the pallet-receiving elementincludes a movable surface for moving the first pallet out of thepalletizing elevator at the lower level.
 5. The system of claim 1,wherein the empty pallet elevator includes a pallet-receiving platformthat is slidably mounted to a wall for movements towards and away theupper and lower levels.
 6. The system of claim 1, wherein the emptypallet conveying mechanism includes at least one of a pusher, aconveyor, a fork and a shuttle.
 7. The system of claim 1, wherein theexpanding/contracting stage includes a first stage secured to a frame, asecond stage that is slidably mounted to the first stage for translationof the second stage onto the first stage between two oppositelongitudinal directions, and a third stage that is slidably mounted tothe second stage for translation of the third stage onto the secondstage between the two opposite longitudinal directions.
 8. The system ofclaim 7, wherein, in operation, the expanding/contracting stage extendsbetween a first position wherein the third stage overlays at leastpartially the empty pallet elevator, and a second position wherein thethird stage overlays at least partially the palletizing elevator.
 9. Thesystem of claim 1, further comprising at least one product infeedconveyor that is positioned at the upper level within reach of the atleast one product picking apparatus for moving products adjacent to theat least one product picking apparatus.
 10. The system of claim 1,wherein the upper level is defined by a raised platform.
 11. The systemof claim 10, wherein the raised platform includes an aperture over thepalletizing elevator, adjacent to the product picking apparatus, thatallows passage for the first pallet and for the products that are movedthereon.
 12. The system of claim 1, wherein the at least one productpicking apparatus includes two product picking apparatuses.
 13. Thesystem of claim 1, wherein the at least one product picking apparatus isin the form of a robot arm equipped with an end of arm tool.
 14. Thesystem of claim 1, wherein products are selected from the groupconsisting of cases, cartons, trays and shrink wrapped bundles.
 15. Asystem for simultaneous infeed of empty pallets and outfeed of a fullpallet, the system comprising: a palletizing elevator for receiving oneof the empty pallets at an upper level and for lowering same from theupper level to a lower level as products are moved onto said one of theempty pallets; an empty pallet elevator for raising another one of theempty pallets to the upper level; and a conveying system with anexpanding/contracting stage at the upper level between the empty palletelevator and the palletizing elevator for moving said another one of theempty pallets from the empty pallet elevator to the palletizing elevatorwhile said one of the empty pallets is moved by the palletizing elevatorduring a filling thereof, the expanding/contracting stage expanding andcontracting between a retracted position and first and second extendedpositions respectively on opposite sides of the retracted position andrespectively over the empty pallet elevator and the palletizingelevator, so that a common stage of the expanding/contracting stage,having an empty pallet support surface that is common to each of the oneof the empty pallets and the another one of the empty pallets, is in thefirst extended position over the empty pallet elevator and the secondextended position over the palletizing elevator on the opposite side ofthe retracted position from the empty pallet elevator, wherein each ofthe first, second extended and retracted positions are disposed at theupper level.
 16. A palletizing method for a palletizing system, themethod comprising: receiving a first pallet with a palletizing elevatorat an upper level and moving the first pallet from the upper level to alower level as products are being moved onto the first pallet; pickingproducts with at least one product picking apparatus adjacent thereofand for moving the products onto the first pallet on the palletizingelevator; moving with an empty pallet elevator a second pallet to theupper level; and moving with an empty pallet conveying mechanism with anexpanding/contracting stage between the empty pallet elevator and thepalletizing elevator, at the upper level, the second pallet from theempty pallet elevator to the palletizing elevator, theexpanding/contracting stage expanding and contracting between aretracted position and first and second extended positions respectivelyon opposite sides of the retracted position and respectively over theempty pallet elevator and the palletizing elevator, so that a commonstage of the expanding/contracting stage, having an empty pallet supportsurface that is common to each of the first and second pallet, is in thefirst extended position over the empty pallet elevator and the secondextended position over the palletizing elevator on the opposite side ofthe retracted position from the empty pallet elevator, wherein each ofthe first, second extended and retracted positions are disposed at theupper level.
 17. The method of claim 16, further comprising: receivingproducts to be palletized on a raised platform; repeatedly andsimultaneously: raising a first empty pallet to the raised platform;moving a second empty pallet, on the raised platform, towards apalletizing area defined by an aperture in the raised platform; andmoving the products on a third pallet at the palletizing area until thethird pallet is filled while the third pallet is lowered from the raisedplatform so that an upper level of the products on the third palletremains generally leveled with the palletizing area; exiting the thirdpallet from under the palletizing area.
 18. The method of claim 17,wherein the third pallet is lowered gradually from the raised platformas the products are moved onto the third pallet.
 19. The method of claim18, wherein the third pallet is lowered by steps so that a top level ofthe products on the third pallet remains generally leveled with theraised platform.
 20. The method of claim 16, further comprisingcentering the first empty pallet after it has been raised to the firstplatform.